The present invention relates generally to the detection and conversion of high frequency electromagnetic energy to electrical signals and, more particularly, to an apparatus and method of directly converting x-rays to electrons for use with computed tomography systems.
Typically, in computed tomography (CT) imaging systems, an x-ray source emits a fan-shaped beam toward an object, such as a patient. The beam, after being attenuated by the object, impinges upon an array of radiation detectors. The intensity of the attenuated beam radiation received at the detector array is typically dependent upon the attenuation of the x-ray beam by the object. Each detector element of the detector array produces a separate electrical signal indicative of the attenuated beam received by each detector element. The electrical signals are transmitted to a data processing system for analysis which ultimately results in the formation of an image.
Generally, the x-ray source and the detector array are rotated about the gantry within an imaging plane and around the object. X-ray sources typically include x-ray tubes, which emit the x-ray beam at a focal point. X-ray detectors typically include a collimator for collimating x-ray beams received at the detector, a scintillator for converting x-rays to light energy adjacent the collimator, and photodiodes for receiving the light energy from the adjacent scintillator.
Typically, each scintillator of a scintillator array converts x-rays to light energy. Each scintillator discharges light energy to a photodiode adjacent thereto. Each photodiode detects the light energy and generates a corresponding electrical signal. The outputs of the photodiodes are then transmitted to a data processing system. Typically, the photodiode array is formed on a silicon chip, therefore, complicated and extremely expensive fabrication techniques are required. As a result, the CT imaging system may be unduly complicated and cost prohibitive.
Furthermore, typical scintillators for CT imaging systems have a limited thickness. Generally, the scintillator thickness must be sufficient to stop penetration of the high frequency energy through the scintillator to the remainder of the detector components. However, for each photodiode to efficiently detect emitting light energy, the scintillator thickness should be thin. As a result, design of typical scintillators requires a scintillator of reduced stopping power which, over time, reduces the overall performance and functional life span of the CT system.
It would therefore be desirable to have a scintillator with increased thickness and stopping power capable of converting high frequency electromagnetic energy directly to electrons and directly transmitting the electrons to a data processing system for CT image construction.
The present invention provides a detector for a CT system that overcomes the aforementioned drawbacks. The detector includes a scintillator for receiving and converting high frequency electromagnetic energy directly to electrons. The detector is further configured to directly conduct the electrons. The detector comprises a compound formed of scintillator bulk and conducting material capable of converting high frequency energy to electrons as well as conducting electrons. The CT system also provides for a gantry having an output for projecting high frequency electromagnetic energy toward the detector and a data processing system for receiving electrons directly from the detector.
In accordance with one aspect of the invention, a detector for a computed tomography system is provided. The detector includes a scintillator array having a plurality of scintillators therein capable of receiving high frequency electromagnetic energy, converting the electromagnetic energy directly to electrons, and transmitting those electrons directly to a data processing system.
In accordance with another aspect of the invention, a composite for an image detection CT system includes both a bulk to directly convert high frequency electromagnetic energy to electrons and a conducting material. The conducting material is also capable of converting the high frequency electromagnetic energy to electrons and is further capable of conducting the electrons to a plurality of electrical interconnects.
The invention also includes a method to provide imaging electrons to a data acquisition system of a CT system. The method includes directing high frequency electromagnetic energy towards a scintillator housing having therein a scintillator. The method further includes providing a scintillator capable of converting high frequency electromagnetic energy directly to electrons and then conducting those electrons to a data acquisition system for CT image construction.
Various other features, objects and advantages of the present invention will be made apparent from the following detailed description and the drawings.